One problem with most beverages, ready-to-eat foods, and other products that require heating is that they are not hot straight out of the container. Rather, they must be heated by external means. Although instant teas or soups can be heated by adding hot or boiling water to the container, this assumes that the user has access to a supply of hot water. Many times this is simply not true. For example, the user may be outdoors or otherwise without access to microwaves, stoves, electricity or heating fuel. Further, in emergency situations, instant access to heated beverages, food or other products may be vital to survival.
A related problem is found in the spa and beauty industries which make wide-spread use of heated waxes and resins to remove unwanted hair and hair follicles from various body parts, such the eyebrow, upper lip, arm pit, bikini line, legs, arms, and other areas of the body. For the purposes of this disclosure, the term “wax” or “resin” is understood to encompass any heated depilatory agent. In a typical wax depilating session, a bulk of wax or similar substance is heated by electrical means in a container, such as a can, tub, or pot. It can be difficult, particularly for a home user without access to specialized heating equipment, to heat and maintain the wax at the correct temperature without dangerously overheating it.
Once heated, the wax is applied to the hair and underlying skin by a spreader tool such as a tongue depressor or applicator. The heated wax is scooped up by the esthetician or home user via the applicator, and spread onto the treatment area in a sufficient amount and allowed to cool or congeal. Multiple dips into the heated wax container are needed to cover the treatment area. After cooling, the user grasps the hardened wax layer and quickly pulls the congealed wax off the skin, thus removing the hair away from the skin. In a soft wax application, the usage is very much the same except with the addition of a gauze or similar strip being applied over the wax as the carrier to lend dimensional stability to the wax as it is being pulled from the treatment area.
In all depilatory wax-based applications, sanitation is a concern as “double dipping” may occur or multiple contacts between the applicator, skin, and bulk wax. Specifically, when the applicator is used against the skin, dead skin cells, hair and debris, and potential pathogens stick to the wax on the applicator. When the operator reloads the applicator by scooping up additional wax from the bulk wax, the bulk wax can be subject to contamination from contact with the skin, dead skin cells, hair and debris on the applicator. In practice, cross contamination from multiple people has been a growing concern, as increased incidences of skin-related illnesses have been reported from “later” customers. For example, skin conditions such as impetigo, herpes simplex, ringworm, scabies, warts and many other conditions including afflictions derived from fungus, viruses, and bacteria can be communicated to later customers via the bulk wax container.
Another complication is that the bulk wax takes a significant period of time to heat, therefore, the treatment and disposal of contaminated wax can be a significant cost in both time and energy. Also, handling large quantities of wax can be a difficult matter, especially in view of the treatment and disposal concerns above.
To solve the various problems outlined above, many solutions have been proposed. For example, instant-hot beverages and soups have been provided in which the outer container includes an inner contents chamber (to hold the beverage, soup or other contents to be heated), a quick-lime chamber, and a water chamber. The user causes the water chamber to communicate with the quick lime chamber, and the combination of water and quick-lime gives rise to a fast exothermic reaction (for example, see U.S. Pat. No. 7,117,684 to Scudder et al.). While these known instant-hot containers provide the user with heated contents, they have drawbacks. First, the quick-lime and water reaction completes very quickly so that although the contents are initially hot, they begin to cool down as soon as the exothermic reaction completes, which may be a matter of only a few minutes. Second, the quick-lime exothermic reaction is extremely hot and can lead to contents that are dangerously hot and thus requires a container that can withstand extremely high temperatures. Finally, the quick-lime and water combination creates a hot slurry that can easily leak out of the container and cause burns unless a complicated one-way valve is provided that allows gas to escape but keeps the slurry inside the reaction area of the container.
Another significant problem with known instant self-heating containers is that the heated slurry tends to only contact the bottom of the contents chamber so that the contents at the bottom of the contents chamber are initially much hotter than the contents at the top of the chamber. Where the contents are dispensed from the top of the outer container, this means that the contents which leave the container first are coolest while the hottest contents remain at the bottom of the contents chamber.
Accordingly, it would be advantageous to provide an instant self-heating food and beverage container that has a long-lasting heat source so that the beverage or food can be maintained at a relatively constant elevated temperature for a relatively long duration of time. There is also a need for an instant self-heating container that dispenses the hottest contents first while allowing the cooler contents to continue heating. A need also exists for an instant self-heating container that heats the entire contents more quickly and uniformly. Similarly, there is a need for a way to rapidly and uniformly heat depilatory wax in single-use containers so that users can quickly apply hot wax without the need for a large container that is subject to contamination. Finally, it would also be advantageous to provide an instant self-heating container that can be made from relatively inexpensive, disposable materials.